Sull'esistenza delle soluzioni delle equazioni differenziali ordinarie in forma implicita negli spazi di Banach

This paper deals with the existence of solutions for the implicit Cauchy problem F(t, x, x)=θ{symbol}B, x(t0)=x0 in a Banach space B. By using the Kuratowski and the Hausdorff measure of non compactness, we prove an existence theorem for the previous problem (Teorema 1.1) and its extension to non compact intervals (Teorema 2.1). These results generalize the previous ones by R. Conti [1] (in the case B=R), G. Pulvirenti [2] and T. Dominguez Benavides [3], [4] (in the general case). In particular, we relax a Lipschitz condition assumed by all of the abovementioned authors. Some applications of Teorema 2.1 are presented. © 1980 Fondazione Annali di Matematica Pura ed Applicata.